The only thing I've found that really works, and isn't dangerous to children or the family pet, is bird netting. I lay it on the ground around my plants and stake it into the ground using landscaping pins (they look like giant staples). Cats hate getting their claws stuck in the netting and it prevents them from digging a potty hole. Works like a charm for me. You don't have to use alot of it ....just cut it up into sections for your specific needs and place it in any open areas around your plants. Pay special attention to areas "behind" your plantings, because cats like a bit of privacy when they do their business and will look for spots that a.) have soft dirt they can dig in easily, and b.) are a bit secluded - a spot where they feel safe.
The netting is almost invisible once you have it down, but you can cover it with a light layer of mulch, if you like.

You can purchase the netting at any home improvement center...same thing with the landscaping pins. I've also seen the netting at Walmart. It isn't expensive.

Renee

Havahart Critter Ridder repellent granules can be effective for cats - Walmart has it here. Or they did, until they started taking apart the gardening department and filling it with Christmas merchandise :)

Thanks, You don't know how much I appreciate the info. The front of my house is begining to stink. Can't smell the flowers for the poo.
Gail

I use moth balls. They don't like the smell and tend to stay away. Need to be replaced when they dissolve. I've used them for years and they're cheap.